Coming back to Atom cursor is slow to appear

Have three projects and one folder in Project tree view and a single markdown text document open in the main tab.

When I click on a web browser window and click back on my markdown text file the cursor takes more than 1.5 s to appear again.

Clicking on any other application window (music player, explorer, terminal, …) has the same delay of the cursor when comming back.

Using

  • Windows 10
  • Atom 1.57.0

Opening a new Atom with just one folder on the Prject view does not show same delay.
If it is a package that is causing this delay, how can I find which one is it?